Exhibit 3.1
 
                       SECOND AMENDED AND RESTATED BYLAWS
                        OF ASCENTIAL SOFTWARE CORPORATION
 
                                    ARTICLE I
 
                                     OFFICES
 
         SECTION 1. Principal Executive Office. The Board of Directors shall fix
the location of the principal executive office of the Corporation at any place
within or outside the State of Delaware. The Board of Directors shall fix and
designate a registered business office and registered agent in the State of
Delaware regardless of whether the Corporation maintains a place of business
there.
 
         SECTION 2. Other Offices. The Board of Directors may at any time
establish branch or subordinate offices at any place or places where the
Corporation is qualified to do business.
 
                                   ARTICLE II
 
                            MEETINGS OF STOCKHOLDERS
 
         SECTION 1. Place of Meetings. Meetings of stockholders shall be held at
any place within or outside the State of Delaware designated by the Board of
Directors. In the absence of any such designation, stockholders' meetings shall
be held at the principal executive office of the Corporation.
 
         SECTION 2. Annual Meetings. The annual meetings of stockholders shall
be held on such day and at such hour as may be fixed by the Board of Directors
within thirteen months subsequent to the later of the date of incorporation of
the Corporation or the last annual meeting of stockholders. At such meeting,
Directors shall be elected and any other proper business may be transacted.
 
         At an annual meeting of the stockholders, only such business shall be
conducted as shall have been properly brought before the meeting. To be properly
brought before an annual meeting, business must be (a) specified in the notice
of meeting (or any supplement thereto) given by or at the direction of the Board
of Directors, (b) otherwise properly brought before the meeting by or at the
direction of the Board of Directors, or (c) otherwise properly brought before
the meeting by a stockholder. For business to be properly brought before an
annual meeting by a stockholder, the stockholder must have given timely notice
thereof in writing to the Secretary of the Corporation. To be timely, a
stockholder's notice must be delivered to or mailed and received at the
principal executive offices of the Corporation not less than one hundred twenty
(120) days prior to the date of such meeting (as set forth in this Section 2). A
stockholder's notice to the Secretary shall set forth as to each matter the
stockholder proposes to bring before the annual meeting (a) a brief description
of the business desired to be brought before the annual meeting, (b) the name
and address, as they appear on the Corporation's books, of the stockholder
proposing such business, (c) the class and number of shares of the Corporation
which are beneficially owned (as such term is defined in Section 4, Paragraph D
of Article Seven of the Corporation's Certificate of Incorporation) by the
stockholder, (d) any material interest of the stockholder in such business and
(e) all other information with respect to each such matter as would have been
required to be included in a proxy statement filed pursuant to Regulation 14A
(17 CFR 240.14a-l
 
                                      -1-
 
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et seq.) as then in effect under the Securities Exchange Act of 1934, as
amended, had proxies been solicited by the Board of Directors with respect
thereto. Notwithstanding anything in the Second Amended and Restated Bylaws to
the contrary, no business shall be conducted at an annual meeting except in
accordance with the procedures set forth in this Section 2. The presiding
officer of an annual meeting shall, if the facts warrant, determine that
business was not properly brought before the meeting in accordance with the
provisions of this Section 2, and if he should so determine, he shall so declare
to the meeting and any such business not properly brought before the meeting
shall not be transacted.
 
         SECTION 3. Special Meetings. Special meetings of the stockholders may
be held for any purpose or purposes unless otherwise proscribed by statute or by
the Certificate of Incorporation. Except as otherwise required by law and
subject to the rights, if any, of the holders of any class or series of stock
having a preference over the Common Stock as to dividends or upon liquidation,
special meetings of the stockholders of the Corporation may be called only by
the Chairman of the Board of Directors, the President of the Corporation or the
Board of Directors pursuant to a resolution approved by a majority of the entire
Board of Directors.
 
         The "call" and the "notice" of any such meeting shall be deemed to be
synonymous.
 
         SECTION 4. Notice of Stockholders' Meetings. All notices of meetings of
stockholders shall be sent or otherwise given in accordance with Section 5 of
this Article II not fewer than ten (10) nor more than sixty (60) days before the
date of the meeting. The notice shall specify the place, date and hour of the
meeting and (i) in the case of a special meeting, the nature of the business to
be transacted, or (ii) in the case of the annual meeting, those matters which
the Board of Directors, at the time of giving the notice, intends to present for
action by the stockholders. The notice of any meeting at which Directors are to
be elected shall include the name of any nominee or nominees whom, at the time
of the notice, management intends to present for election.
 
         SECTION 5. Manner of Giving Notice; Affidavit of Notice. Written notice
of any meeting of stockholders shall be given. If mailed, notice shall be deemed
to have been given at the time when delivered personally or deposited in the
United States mail, postage prepaid.
 
         An affidavit of the mailing or other means of giving any notice of any
stockholders' meeting shall be executed by the secretary, assistant secretary,
or any transfer agent of the Corporation giving the notice, and shall be filed
and maintained in the minute book of the Corporation.
 
         SECTION 6. Quorum. At any meeting of the stockholders, the holders of a
majority of all of the shares of the stock entitled to vote at the meeting,
present in person or by proxy, shall constitute a quorum for all purposes,
unless or except to the extent that the next sentence is applicable or the
presence of a larger number may be required by law. Where a separate vote by a
class or classes is required, a majority of the shares of such class or classes
present in person or represented by proxy shall constitute a quorum entitled to
take action with respect to that vote on that matter. If a quorum shall fail to
attend any meeting, the chairman of the meeting or the holders of a majority of
the shares of stock entitled to vote who are present, in person or by proxy, may
adjourn the meeting to another place, date, or time.
 
         SECTION 7. Adjourned Meetings and Notice Thereof. When a stockholders'
meeting is adjourned to another time or place, notice of the adjourned meeting
need not be given if the time
 
                                      -2-
 
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and place thereof are announced at the meeting at which the adjournment is
taken; except that if the adjournment is for more than thirty days or if the
Board of Directors shall set a new record date, notice of any adjourned meeting
shall be given to each stockholder of record entitled to vote at the adjourned
meeting in accordance with Sections 4 and 5 of this Article II. At the adjourned
meeting, the Corporation may transact any business which might have been
transacted at the original meeting.
 
         SECTION 8. Voting. Except as otherwise required by the Certificate of
Incorporation or the General Corporation Law of Delaware, each outstanding
share, regardless of class, shall be entitled to one vote on each matter
submitted to a vote of stockholders. Vote may be by voice or by ballot.
 
         Any holder of shares entitled to vote on any matter may vote part of
the shares in favor of the proposal and refrain from voting the remaining shares
or vote them against the proposal but if the stockholder fails to specify the
number of shares such stockholder is voting affirmatively, it shall be
conclusively presumed that the stockholder's approving vote is with respect to
all shares said stockholder is entitled to vote.
 
         SECTION 9. Waiver of Notice or Consent by Absent Stockholders. The
transactions of any meeting of stockholders, either annual or special, however
called and noticed, and wherever held, shall be as valid as though had at a
meeting duly held after regular call and notice, if a quorum is present either
in person or by proxy, and if, either before or after the meeting, each person
entitled to vote, not present in person or by proxy, signs a written waiver of
notice, or a consent to the holding of such meeting, or an approval of the
minutes thereof. The waiver of notice or consent need not specify either the
business to be transacted or the purpose of any annual or special meeting of
stockholders. All such waivers, consents, or approvals shall be filed with the
corporate records or made a part of the minutes of the meeting.
 
         Attendance of a person at a meeting shall constitute a waiver of notice
of such meeting, except when a person objects, at the beginning of the meeting,
to the transaction of any business because the meeting is not lawfully called or
convened; and except that attendance at a meeting is not a waiver of any right
to object to the consideration of matters not included in the notice of the
meeting if that objection is expressly made at the meeting.
 
         SECTION 10. Stockholder Action; How Taken. No action required or
permitted to be taken at any annual or special meeting of stockholders of the
Corporation may be taken without a meeting, and the power of stockholders to
consent in writing, without a meeting, to the taking of any action is
specifically denied.
 
         SECTION 11. Proxies. Every person entitled to vote for Directors or on
any other matter shall have the right to do so either in person (including by
means of remote communications, if any, by which stockholders may be deemed to
be present in person and vote at such meeting) or by one or more agents
authorized by a proxy executed or transmitted in a manner permitted by the
General Corporation Law of the State of Delaware by the stockholder or such
stockholder's authorized agent and delivered (including by electronic
transmission) to the secretary of the Corporation. A validly executed or
transmitted proxy which does not state that it is irrevocable and is not coupled
with an interest shall continue in full force and effect unless (i) revoked by
the person executing or transmitting it, before the vote pursuant to that proxy,
by a writing delivered to the Corporation stating that the proxy is revoked, or
by a subsequent proxy executed or transmitted by, or attendance at the meeting
and voting in person by, the person executing or transmitting the proxy; or (ii)
written notice of the death or incapacity of the maker
 
                                      -3-
 
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of that proxy is received by the Corporation before the vote pursuant to that
proxy is counted; provided, however, that no proxy shall be valid after the
expiration of three years from the date of the proxy, unless otherwise provided
in the proxy.
 
         SECTION 12. Inspectors of Election. Before any meeting of stockholders,
the Board of Directors may appoint any persons other than nominees for office to
act as inspectors of election at the meeting or its adjournment. If no
inspectors of election are so appointed, the chairman of the meeting may appoint
inspectors of election at the meeting.
 
         These inspectors shall:
 
         (a) Determine the number of shares outstanding and the voting power of
each, the shares represented at the meeting, the existence of a quorum, and the
authenticity, validity, and effect of proxies;
 
         (b)  Receive votes, ballots, or consents;
 
         (c) Hear and determine all challenges and questions in any way arising
in connection with the right to vote;
 
         (d) Count and tabulate all votes or consents;
 
         (e) Determine when the polls shall close;
 
         (f) Determine the results; and
 
         (g) Do any other acts that may be proper to conduct the elections or
votes with fairness to all stockholders.
 
         SECTION 13. Stockholders' Lists. The Secretary or Assistant Secretary,
who shall have charge of the stock ledger, shall prepare and make, at least ten
(10) days before every meeting of stockholders, a complete list of the
stockholders entitled to vote at the meeting, arranged in alphabetical order,
and showing the address of each stockholder and the number of shares registered
in the name of each stockholder. Such list shall be open to the examination of
any stockholder, for any purpose germane to the meeting, during ordinary
business hours, for a period of at least ten (10) days prior to the meeting,
either at a place within the city where the meeting is to be held, which place
shall be specified in the notice of the meeting, or, if not so specified, at the
place where the meeting is to be held. The list shall also be produced and kept
at the time and place of the meeting during the whole time thereof, and may be
inspected by any stockholder who is present. This list shall presumptively
determine the identity of the stockholders entitled to vote at the meeting and
the number of shares held by each of them.
 
                                   ARTICLE III
 
                                    DIRECTORS
 
         SECTION 1. Management. The property, business and affairs of the
Corporation shall be managed by or under the direction of a Board of Directors.
The number of Directors of the Corporation (including Directors to be elected by
the holders of any one or more series of Preferred Stock voting separately as a
class or classes) shall be five (5). As used in these Second Amended and
Restated Bylaws, the terms "whole Board" or "whole Board of Directors" mean the
 
                                      -4-
 
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total number of Directors which the Corporation would have if there were no
vacancies. In addition to the powers and authorities by these Second Amended and
Restated Bylaws and the Certificate of Incorporation expressly conferred upon
it, the Board of Directors may exercise all such powers of the Corporation, and
do all such lawful acts and things as are not by statute or by the Certificate
of Incorporation or by these Second Amended and Restated Bylaws directed or
required to be exercised or done by the stockholders.
 
         SECTION 2. Classes. The members of the whole Board of Directors, other
than those who may be elected by the holders of any Preferred Stock, or series
thereof, shall be divided into three (3) classes (to be designated as Class I,
Class II and Class III), with the term of office of one class expiring each
year. Subject to any shorter or longer term which may be applicable to a
director elected by any series of Preferred Stock voting separately as a class,
at each annual meeting of stockholders the successors to the class of Directors
whose term shall then expire shall be elected to hold office for a term expiring
at the third succeeding annual meeting and until their respective successors
shall be elected and qualify or until their respective earlier resignation or
removal.
 
         SECTION 3. Vacancies and Newly Created Directorships. Except for
directorships created pursuant to Article Four of the Certificate of
Incorporation relating to the rights of holders of Preferred Stock, or any
series thereof, and except for vacancies in such directorships, any vacancies in
the Board of Directors for any reason, and any newly created Directorships
resulting from any increase in the number of Directors, may be filled only by
the Board of Directors, acting by a majority of the Directors then in office,
although less than a quorum, and any Directors so chosen shall hold office until
the next election of the class for which such Directors shall have been chosen
and until their respective successors shall be elected and qualified or until
their respective earlier resignation or removal. No decrease in the number of
Directors shall shorten the term of any incumbent Director.
 
         SECTION 4. Removal of Directors. Notwithstanding any other provisions
of these Second Amended and Restated Bylaws (and notwithstanding the fact that
some lesser percentage may be specified by law or these Second Amended and
Restated Bylaws), any Director or the entire Board of Directors of the
Corporation, except for Directors elected by one or more series of Preferred
Stock, voting separately as a class, may be removed at any time, but only for
cause and only by the affirmative vote of the holders of at least a majority of
the Total Voting Power of the then outstanding shares of Voting Stock,
considered for this purpose as one class (it being understood that for purposes
of this Section 4, each share of the Voting Stock shall have the number of votes
granted to it pursuant to Article Four of the Corporation's Certificate of
Incorporation). For the purposes of this Section 4, (i) the term "Total Voting
Power" shall mean the aggregate of all votes of all outstanding shares of Voting
Stock; and (ii) the term "Voting Stock" shall mean the shares of all classes of
capital stock of the Corporation entitled to vote on removal of any Director or
the entire Board of Directors in the manner provided in this Section 4 (except
that if the next succeeding sentence is operative, then the outstanding shares
of Preferred Stock shall not be considered "Voting Stock" for purposes of this
Section 4). Notwithstanding the foregoing, and except as otherwise required by
law, whenever the holders of any one or more series of Preferred Stock shall
have the right, voting separately as a class, to elect one or more Directors of
the Corporation, the provisions of this Article III, Section 4 shall not apply
with respect to the Director or Directors elected by such holders of Preferred
Stock.
 
         SECTION 5. Notification of Nominations. Subject to the rights of
holders of any class or series of Preferred Stock, nominations for the election
of Directors may be made by the Board of Directors or a proxy committee
appointed by the Board of Directors or by any stockholder
 
                                      -5-
 
<PAGE>
 
entitled to vote in the election of Directors generally. However, any
stockholder entitled to vote in the election of Directors may nominate one or
more persons for election of Directors at a meeting only if written notice of
such stockholder's intent to make such nomination or nominations has been given,
either by personal delivery or by United States mail, postage prepaid, to the
Secretary of the Corporation not later than (i) with respect to an election to
be held at an annual meeting of stockholders, one hundred and twenty (120) days
in advance of the date of such meeting (as set forth in Section 2 of Article II
of these Second Amended and Restated Bylaws), and (ii) with respect to an
election to be held at a special meeting of stockholders for the election of
Directors, the close of business on the seventh (7th) day following the date on
which notice of such meeting is first given to stockholders. Each such notice
shall set forth: (a) the name and address of the stockholder who intends to make
the nomination and of the person or persons to be nominated; (b) a
representation that the stockholder is a holder of record of stock of the
Corporation entitled to vote at such meeting and intends to appear in person or
by proxy at the meeting to nominate the person or persons specified in the
notice; (c) the name and address, as they appear on the Corporation's books, of
such stockholder; (d) the class and number of shares of the Corporation which
are beneficially owned (as such term is defined in Section 4, Paragraph D of
Article Seven of the Corporation's Certificate of Incorporation) by the
nominating stockholder an each nominee proposed by such stockholder; (e) a
description of all arrangements or understandings between the stockholder and
each nominee and any other person or persons (naming such person or persons)
pursuant to which the nomination or nominations are to be made by the
stockholder; (f) such other information regarding each nominee proposed by such
stockholder as would have been required to be included in a proxy statement
filed pursuant to Regulation 14A (17 CFR 240.14a-1 et seq.) as then in effect
under the Securities Exchange Act of 1934, as amended, had the nominee been
nominated, or intended to be nominated, by the Board of Directors; and (g) the
consent of each nominee to serve as a Director of the Corporation if so elected.
The chairman of the meeting may refuse to acknowledge the nomination of any
person not made in compliance with the foregoing procedure.
 
         SECTION 6. Place of Meetings and Meetings by Telephone. Meetings of the
Board of Directors shall be held at any place within or without the State of
Delaware which may be designated in the notice of the meeting, or, if not stated
in the notice or there is no notice, designated by resolution of the Board. In
the absence of such designation, meetings of the Board of Directors shall be
held at the principal executive office of the Corporation. Members of the Board
may participate in a regular or special meeting through use of conference
telephone or similar communications equipment, so long as all members
participating in such meeting can hear one another. Participation in a meeting
pursuant to this Section 6 of Article III constitutes presence in person at such
meeting.
 
         SECTION 7. Annual Meeting. Immediately before or after each annual
meeting of the stockholders, the Board of Directors shall hold a regular meeting
for the purpose of organization, the election of officers and the transaction of
other business. No notice of such meeting need be given.
 
         SECTION 8. Other Regular Meetings. The Board of Directors may provide
by resolution the time and place for the holding of regular meetings of the
Board; provided, however, that if the date so designated falls upon a legal
holiday, then the meeting shall be held at the same time and place on the next
succeeding day which is not a legal holiday. No further notice of such regular
meetings of the Board need be given.
 
         SECTION 9. Special Meetings. Special meetings of the Board of Directors
for any purpose or purposes may be called at any time by the chairman of the
Board or the president or
 
                                      -6-
 
<PAGE>
 
any vice president or the secretary or any two Directors.
 
         Notice of the time and place of special meetings shall be delivered
personally or by telephone to each Director or sent by first-class mail,
overnight courier, or telegram, charges prepaid, addressed to each Director at
that Director's address as it is shown on the records of the Corporation or his
usual place of business. In case the notice is mailed, it shall be deposited in
the United States mail at least three (3) days before the time of the holding of
the meeting. In case the notice is delivered personally, or by telephone,
overnight courier, or telegram, it shall be delivered personally or by telephone
or to the courier or telegraph company at least forty-eight (48) hours before
the time of the holding of the meeting. Any oral notice given personally or by
telephone may be communicated either to the Director or to a person at the
office of the Director who the person giving the notice has reason to believe
will promptly communicate it to the Director. The notice need not specify the
purpose of the meeting nor the place if the meeting is to be held at the
principal executive office of the Corporation.
 
         SECTION 10. Quorum. A majority of the authorized number of Directors
shall constitute a quorum for the transaction of business except to adjourn as
provided in Section 12 of this Article III. Every act or decision done or made
by a majority of the Directors present at a meeting duly held at which a quorum
is present shall be the act of the Board of Directors, unless the Certificate of
Incorporation, or the General Corporations Law of Delaware, specifically
requires a greater number. A meeting at which a quorum is initially present may
continue to transact business, notwithstanding the withdrawal of Directors, if
any action taken is approved by at least a majority of the required quorum for
such meeting.
 
         SECTION 11. Waiver of Notice. Notice of a meeting shall be deemed given
to any Director who attends the meeting without protesting before or at its
commencement, the lack of notice to such director.
 
         The transactions of any meeting of the Board of Directors, however
called and noticed or wherever held, shall be as valid as though had at a
meeting duly held after regular call and notice if a quorum is present and if,
either before or after the meeting, each of the Directors not present signs a
written waiver of notice, a consent to holding the meeting or an approval of the
minutes thereof. The waiver of notice or consent need not specify the purpose of
the meeting. All such waivers, consents and approvals shall be filed with the
corporate records or made a part of the minutes of the meeting.
 
         SECTION 12. Adjournment. Any meeting of the Board of Directors, whether
or not a quorum is present, may be adjourned to another time and place by the
vote of a majority of the Directors present. If a meeting is adjourned for more
than 24 hours, notice of the time and place of the reconvened adjourned meeting
shall be given to Directors absent at the time of adjournment before the time of
the reconvened adjourned meeting.
 
         SECTION 13. Action Without Meeting. Any action required or permitted to
be taken by the Board of Directors may be taken without a meeting, if all
members of the board shall individually or collectively consent in writing to
such action. Such written consent or consents shall be filed with the minutes of
the proceedings of the Board. Such action by written consent shall have the same
force and effect as a unanimous vote of such Directors.
 
         SECTION 14. Fees and Compensation of Directors. Unless otherwise
restricted by the Certificate of Incorporation, the Board of Directors may, by
resolution, fix the compensation to be paid Directors for serving as Directors
of the Corporation and may, by resolution, fix a sum
 
                                      -7-
 
<PAGE>
 
which shall be allowed and paid for attendance at each meeting of the Board of
Directors and may provide for reimbursement of expenses incurred by Directors in
attending each meeting; provided that nothing herein contained shall be
construed to preclude any Director from serving the Corporation in any other
capacity and receiving his regular compensation therefor. Members of special or
standing committees may be allowed similar compensation for attending committee
meetings.
 
                                   ARTICLE IV
 
                                   COMMITTEES
 
         SECTION 1. Committees. The Board of Directors may, by resolution
adopted by a majority of the authorized number of Directors, designate such
committees, each consisting of one or more Directors, as it may from time to
time deem advisable to perform such general or special duties as may from time
to time be delegated to any such committee by the Board of Directors, subject to
the limitations contained in the General Corporations Law of Delaware, or
imposed by the Certificate of Incorporation or by these Second Amended and
Restated Bylaws. Any committee so designated may exercise the power and
authority of the Board of Directors to declare a dividend, to authorize the
issuance of stock or to adopt a certificate of ownership and merger pursuant to
Section 253 of the General Corporation Law of Delaware if the resolution which
designates the committees or a supplemental resolution of the Board of Directors
so provides. The Board may designate one or more Directors as alternate members
of any committee, who may replace any absent member at any meeting of the
committee.
 
         SECTION 2. Minutes. Each committee shall keep regular minutes of its
proceedings, which shall be filed with the Secretary.
 
         SECTION 3. Meetings. Except as otherwise provided in these Second
Amended and Restated Bylaws or by resolution of the Board of Directors, each
committee shall adopt its own rules governing the time and place of holding and
the method of calling its meetings and the conduct of its proceedings and shall
meet as provided by such rules. Unless otherwise provided by such rules or by
resolution of the Board of Directors, committee meetings shall be governed by
Sections 11, 12 and 13 and Article III of these Second Amended and Restated
Bylaws.
 
         SECTION 4. Term of Office of Committee Members. The term of office of
any committee member shall be as provided in the resolution of the Board of
Directors designating such committee member but shall not exceed such committee
member's term as a Director. Any member of a committee may be removed at any
time by resolution adopted by a majority of the Directors, either present at a
meeting of the Board or by written approval thereof.
 
                                    ARTICLE V
 
                                    OFFICERS
 
         SECTION 1. Officers. The officers of the Corporation shall be a Chief
Executive Officer, a Vice President, a Secretary, and a Treasurer, who shall be
the Chief Financial Officer of the Corporation. The Corporation may also have,
at the discretion of the Board of Directors, a Chairman of the Board, a
President, one or more additional Vice Presidents, one or more Assistant
Treasurers, and such other officers as may be appointed in accordance with the
provisions of Section 3 of this Article V. One person may hold two or more
offices.
 
                                      -8-
 
<PAGE>
 
         SECTION 2. Election. The officers of the Corporation, except such
officers as may be appointed in accordance with the provisions of Section 3 and
5 of this Article V, shall be chosen annually by the Board of Directors and each
shall hold office until such officer shall resign or shall be removed or
otherwise disqualified to serve, or such officer's successor shall be elected
and qualified.
 
         SECTION 3. Subordinate Officers, Etc. The Board of Directors may
appoint, or may empower the president to appoint, such other officers as the
business of the Corporation may require, each of whom shall hold office for such
period, have such authority and perform such duties as are provided in these
Second Amended and Restated Bylaws or as the Board of Directors may from time to
time determine.
 
         SECTION 4. Removal and Resignation of Officers. Any officer may be
removed, either with or without cause, by a majority of the Directors at the
time in office, at any regular or special meeting of the Board, or, except in
case of an officer chosen by the Board of Directors, by an officer upon whom
such power of removal may be conferred by the Board of Directors.
 
         Any officer may resign at any time by giving written notice to the
Corporation. Any such resignation shall take effect at the date of the receipt
of such notice or at any later time specified therein; and, unless otherwise
specified therein, the acceptance of such resignation shall not be necessary to
make it effective.
 
         SECTION 5. Vacancies in Office. A vacancy in any office because of
death, resignation, removal, disqualification or any other cause shall be filled
in the manner prescribed in these Second Amended and Restated Bylaws for regular
appointments to such office.
 
         SECTION 6. Chairman of The Board. The Chairman of the Board, if there
shall be such an officer, shall, if present, preside at all meetings of the
Board of Directors, and exercise and perform such other powers and duties as may
be from time to time assigned to him or her by the Board of Directors or
prescribed by these Second Amended and Restated Bylaws.
 
         SECTION 7. Chief Executive Officer. The Chief Executive Officer shall,
subject to the provisions of these Second Amended and Restated Bylaws and to the
direction of the Board of Directors, and the Chairman of the Board perform all
duties and have all powers which are commonly incident to the office of chief
executive officer of a corporation, and shall exercise and perform such other
powers and duties as may be from time to time assigned to him by the Board of
Directors or the Chairman of the Board, or prescribed by these Second Amended
and Restated Bylaws.
 
         SECTION 8. President. Subject to such supervisory powers, if any, as
may be given by the Board of Directors to the Chairman of the Board or Chief
Executive Officer, if there shall be such officers, the President shall be the
chief operating officer of the Corporation and shall, subject to the control of
the Board of Directors, have general supervision, direction, and control of the
business and officers of the Corporation. He or she shall have the general
powers and duties of management usually vested in the office of president and
chief operating officer of a corporation, and shall have such other powers and
duties as may be prescribed by the Board of Directors or by these Second Amended
and Restated Bylaws. In the event that the Board of Directors does not appoint
an individual to serve as President of the Corporation, then all of the duties
and responsibilities specified in Section 8 shall be given to the Chief
Executive Officer, and all references in the Second Amended and Restated Bylaws
to the President shall be deemed to refer to the Chief Executive Officer.
 
                                      -9-
 
<PAGE>
 
         SECTION 9. Vice President. In the absence or disability of the
President, the Vice Presidents in order of their rank as fixed by the Board of
Directors, or if not ranked, the Vice President designated by the Board of
Directors, shall perform the duties of the President, and when so acting shall
have all the powers of, and be subject to all the restrictions upon, the
President. The Vice Presidents shall have such other powers and perform such
other duties as from time to time may be prescribed for them respectively by the
Board of Directors of these Second Amended and Restated Bylaws.
 
         SECTION 10. Secretary. The Secretary shall keep, or cause to be kept, a
book of minutes in written form of the proceedings of the Board of Directors,
committees of the Board, and stockholders. Such minutes shall include all
waivers of notice, consents to the holding of meetings, or approvals of the
minutes of meetings executed pursuant to these Second Amended and Restated
Bylaws or the General Corporations Law of Delaware. The secretary shall keep, or
cause to be kept at the principal executive office or at the office of the
Corporation's transfer agent or registrar, a record of its stockholders, giving
the names and addresses of all stockholders and the number and class of shares
held by each.
 
         The Secretary shall give or cause to be given, notice of all meetings
of the stockholders and of the Board of Directors required by these Second
Amended and Restated Bylaws or by law to be given, and shall keep the seal of
the Corporation in safe custody, and shall have such other powers and perform
such other duties as may be prescribed by the Board of Directors or these Second
Amended and Restated Bylaws.
 
         SECTION 11. Chief Financial Officer. The Chief Financial Officer shall
keep and maintain, or cause to be kept and maintained, adequate and correct
books and records of account in written form or any other form capable of being
converted into written form.
 
         The Chief Financial Officer shall deposit all monies and other
valuables in the name and to the credit of the Corporation with such
depositaries as may be designated by the Board of Directors. He shall disburse
all funds of the Corporation as may be ordered by the Board of Directors, shall
render to the President and Directors, whenever they request it, an account of
all of his transactions as Chief Financial Officer and of the financial
condition of the Corporation, and shall have such other powers and perform such
other duties as may be prescribed by the Board of Directors or by these Second
Amended and Restated Bylaws.
 
         SECTION 12. Compensation. The compensation of the officers shall be
fixed from time to time by the Board of Directors, and no officer shall be
prevented from receiving such compensation by reason of the fact that he is also
a Director of the Corporation.
 
                                   ARTICLE VI
 
                                 INDEMNIFICATION
 
         Section 1. Right to Indemnification. Each person who was or is made a
party or is threatened to be made a party to or is involved in any action, suit
or proceeding, whether civil, criminal, administrative, investigative, or
appellate ("Proceeding"), by reason of the fact that he or she is or was a
Director or officer of the Corporation or is or was serving at the request of
the Corporation as a Director or officer of another Corporation or of a
partnership, joint venture, trust or other enterprise, including service with
respect to employee benefit plans, whether the basis of such Proceeding is
alleged action in an official capacity as a Director or officer or in any other
 
                                      -10-
 
<PAGE>
 
capacity while serving as a Director or officer shall be indemnified and held
harmless by the Corporation to the fullest extent not prohibited by the General
Corporation Law of Delaware, as the same exists or may hereafter be amended
(but, in the case of any such amendment, only to the extent that such amendment
permits the Corporation to provide broader indemnification rights than said Law
permitted the Corporation to provide prior to such amendment) against all
expenses, liability and loss (including, without limitation, attorneys' fees,
judgments, fines, ERISA excise taxes or penalties and amounts paid or to be paid
in settlement) reasonably incurred or suffered by such person in connection
therewith or in connection with the investigation, defense, settlement or appeal
of such Proceeding and such indemnification shall continue as to a person who
has ceased to be a Director or officer and shall inure to the benefit of his or
her heirs, executors and administrators; provided, however that, except as
provided in Section 2 of this Article VI, the Corporation shall indemnify any
such person seeking indemnity in connection with a Proceeding (or part thereof)
initiated by such person only if such Proceeding (or part thereof) was
authorized by the Board of Directors of the Corporation. The right to
indemnification conferred by this Section shall include the right to be paid by
the Corporation expenses incurred in defending any such Proceeding in advance of
its final disposition (hereinafter an "advancement of expenses"); provided,
however that, if required by the General Corporation Law of Delaware, an
advancement of expenses incurred by a Director or officer in his or her capacity
as a Director or officer (and not in any other capacity in which service was or
is rendered by such person while a Director or officer, including, without
limitation, service to an employee benefit plan) shall be made only upon
delivery to the Corporation of an undertaking, by or on behalf of such Director
or officer, to repay all amounts so advanced if it shall ultimately be
determined by final judicial decision from which there is no further right to
appeal that such Director or officer is not entitled to be indemnified under
this Section or otherwise. Any other provision herein to the contrary
notwithstanding, the Corporation shall not be obligated under these Second
Amended and Restated Bylaws to indemnify the indemnitee for any amounts paid in
settlement of a Proceeding unless the Corporation consents to such settlement
which consent shall not be unreasonably withheld.
 
         SECTION 2. Right of Indemnitee to Bring Suit. If a claim under Section
1 of this Article VI is not paid in full by the Corporation within sixty (60)
days after a written claim has been received by the Corporation, except in the
case of a claim for an advancement of expenses, in which case the applicable
period shall be twenty (20) days, the indemnitee may at any time thereafter
bring suit against the Corporation to recover the unpaid amount of the claim. If
successful in whole or in part in any such suit, or in a suit brought by the
Corporation to recover an advancement of expenses pursuant to the terms of an
undertaking, the indemnitee shall be entitled to be paid also the expense of
prosecuting or defending such suit. In (i) any suit brought by the indemnitee to
enforce a right to indemnification hereunder (but not in a suit brought by the
indemnitee to enforce a right to an advancement of expenses) it shall be a
defense that, and (ii) in any suit by the Corporation to recover an advancement
of expenses pursuant to the terms of an undertaking the Corporation shall be
entitled to recover such expenses upon a final adjudication that, the indemnitee
has not met the applicable standard of conduct set forth under the General
Corporation Law of Delaware. Neither the failure of the Corporation (including
its Board of Directors, independent legal counsel, or its stockholders) to have
made a determination prior to the commencement of such action that
indemnification of the indemnitee is proper in the circumstances because he or
she has met the applicable standard of conduct set forth in the General
Corporation law of Delaware, nor an actual determination by the Corporation
(including its Board of Directors, independent legal counsel, or its
stockholders) that the indemnitee has not met such applicable standard of
conduct, shall create a presumption that the indemnitee has not met the
applicable standard of conduct or, in the case of a suit brought by the
indemnitee, be a defense to such a suit. In a suit brought by the indemnitee to
enforce a right to indemnification or
 
                                      -11-
 
<PAGE>
 
to an advancement of expenses hereunder, or by the Corporation to recover an
advancement of expenses pursuant to the terms of an undertaking, the burden of
proving that the indemnitee is not entitled to be indemnified, or to such
advancement of expenses, under this Article or otherwise shall be on the
Corporation.
 
         SECTION 3. Indemnification of Employees and Agents of the Corporation.
The Corporation may, to the extent authorized from time to time by the Board of
Directors, grant rights to indemnification, and to the advancement of expenses
to any employee or agent of the Corporation to the fullest extent of the
provisions of this Article with respect to the indemnification of and
advancement of expenses to Directors and officers of the Corporation.
 
         SECTION 4. Non-Exclusivity of Rights. The rights conferred on any
person by this Article VI shall not be exclusive of any other right which such
person may have or hereafter acquire under any statute, provision of the
Certificate of Incorporation or these Second Amended and Restated Bylaws,
agreement, vote of stockholders or disinterested Directors, insurance policy, or
otherwise. Nothing contained herein shall limit in any way any right which the
Corporation may have to make additional indemnifications with respect to the
same or different persons or classes of persons.
 
         SECTION 5. Indemnification Contracts. The Board of Directors is
authorized to enter into a contract with any Director, officer, employee or
agent of the Corporation, or any person serving at the request of the
Corporation as a director, officer, employee or agent of another corporation,
partnership, joint venture, trust or other enterprise, including employee
benefit plans, providing for indemnification rights equivalent to or, if the
Board of Directors so determines, greater than, those provided for in this
Article VI.
 
         SECTION 6. Insurance. The Corporation may maintain insurance, at its
expense, to protect itself and any such director, officer, employee or agent of
the Corporation or another corporation, partnership, joint venture, trust or
other enterprise against any such expense, liability or loss, whether or not the
Corporation would have the power to indemnify such person against such expense,
liability or loss under the General Corporation Law of Delaware.
 
         SECTION 7. Severability. If any provision of this Article or the
application of any such provision to any person or circumstance is held invalid,
illegal or unenforceable for any reason whatsoever, the remaining provisions of
this Article and the application of such provision to other persons or
circumstances shall not be affected thereby and to the fullest extent legally
permissible the court finding such provision invalid, illegal or unenforceable
shall modify and construe the provision so as to render it valid and enforceable
as against all persons or entities and to give the maximum possible protection
to persons subject to indemnification hereby. Without limiting the generality of
the foregoing, if any officer or Director of the Corporation or any person who
is or was serving at the request of the Corporation as a director, officer,
employee or agent of another corporation or of a partnership, joint venture,
trust or other enterprise, including service with respect to employee benefit
plans is entitled under any provision of this Article, to indemnification by the
Corporation for some or a portion of the expenses, liability and loss (including
without limitation attorney's fees, judgments, fines, ERISA excise taxes or
penalties and amounts paid or to be paid in settlement) reasonably incurred or
suffered by such person in connection with any threatened, pending or completed
action, suit or proceeding, whether civil, criminal, administrative,
investigative or appellate, but not, however, for the total amount thereof, the
 
                                      -12-
 
<PAGE>
 
Corporation shall nevertheless indemnify such person for the portion thereof to
which such person is entitled.
 
         SECTION 8. Effect of Amendment. The rights granted by this Article
shall be vested in each person entitled to indemnification hereunder as a
bargained-for, contractual condition of such person's acceptance of his election
or appointment in any of the capacities set for in Section 1 of this Article.
Any amendment, repeal or modification of any provision of this Article VI by the
stockholders or the Directors of the Corporation shall not adversely affect any
right of protection of a Director or officer of the Corporation existing at the
time of such amendment, repeal or modification.
 
                                   ARTICLE VII
 
                               RECORDS AND REPORTS
 
         SECTION 1. Maintenance and Inspection of Books and Records. The
Corporation shall keep at its principal executive office, or at the office of
its transfer agent or registrar, if either be appointed and as determined by
resolution of the Board of Directors, a record of its stockholders, giving the
names and addresses of all stockholders and the number and class of shares held
by each stockholder. The Corporation shall also keep at its principal executive
office the original or a copy of the Second Amended and Restated Bylaws as
amended to date and its other books and records.
 
         Any stockholder of the Corporation of record, in person or by attorney
or other agent shall, upon written demand under oath stating the purpose
thereof, have the right during the usual hours for business to inspect for any
proper purpose the Corporation's stock ledger, a list of its stockholders, and
its other books and records and to make copies or extracts therefrom. A proper
purpose shall mean a purpose reasonably related to such person's interest as a
stockholder. In every instance where an attorney or other agent shall be the
person who seeks the right to inspection, the demand under oath shall be
accompanied by a power of attorney or such other writing which authorizes the
attorney or other agent to so act on behalf of the stockholder.
 
         SECTION 2. Inspection by Directors. Any Director shall have the right
to examine the Corporation's stock ledger, a list of its stockholders and its
other books and records for a purpose reasonably related to his or her position
as a Director.
 
                                  ARTICLE VIII
 
                            GENERAL CORPORATE MATTERS
 
         SECTION 1. Regulations. The Board of Directors shall have power and
authority to make all such rules and regulations as it may deem expedient
concerning the issue, transfer, conversion and registration of certificates for
shares of stock of the Corporation, not inconsistent with the laws of Delaware,
the Certificate of Incorporation of the Corporation and these Second Amended and
Restated Bylaws.
 
         SECTION 2. Fixing Record Date. In order that the Corporation may
determine the stockholders entitled to notice of or to vote at any meeting of
stockholders, or to receive payment of any dividend or other distribution or
allotment of any rights or to exercise any rights in respect of any change,
conversion or exchange of stock or for the purpose of any other lawful action,
the Board of Directors may fix a record date, which record date shall not
precede the date on which
 
                                      -13-
 
<PAGE>
 
the resolution fixing the record date is adopted and which record date shall not
be more than sixty (60) nor less than ten (10) days before the date of any
meeting of stockholders, nor more than sixty (60) days prior to the time for
such other action as hereinbefore described, provided, however, that if no
record date is fixed by the Board of Directors, the record date for determining
stockholders entitled to notice of or to vote at a meeting of stockholders shall
be at the close of business on the day next preceding the day on which notice is
given or, if notice is waived, at the close of business on the day next
preceding the day on which the meeting is held, and, for determining
stockholders entitled to receive payment of any dividend or other distribution
or allotment of rights or to exercise any rights of change, conversion or
exchange of stock or for any other purpose, the record date shall be at the
close of business on the day on which the Board of Directors adopts a resolution
relating thereto.
 
         A determination of stockholders of record entitled to notice of or to
vote at a meeting of stockholders shall apply to any adjournment of the meeting;
provided, however, that the Board of Directors may fix a new record date for the
adjourned meeting.
 
         SECTION 3. Checks, Drafts, Evidences of Indebtedness. All checks,
drafts, or other orders for payment of money, notes, or other evidences of
indebtedness, issued in the name of or payable to the Corporation, shall be
signed or endorsed by such person or persons and in such manner as, from time to
time, shall be determined by resolution of the Board of Directors.
 
         SECTION 4. Corporate Contracts and Instruments; How Executed. The Board
of Directors, except as otherwise provided in these Second Amended and Restated
Bylaws, may authorize any officer of officers, agent or agents, to enter into
any contract or execute any instrument in the name of and on behalf of the
Corporation, and this authority may be general or confined to specific
instances; and, unless so authorized or ratified by the Board of Directors or
within the agency power of an officer, no officer, agent, or employee shall have
any power or authority to bind the Corporation by any contract or engagement or
to pledge its credit or to render it liable for any purpose or for any amount.
 
         SECTION 5. Certificate for Shares. A certificate or certificates for
shares of the capital stock of the Corporation shall be issued to each
stockholder when any of these shares are fully paid, and the Board of Directors
may authorize the issuance of certificates or shares as partly paid provided
that these certificates shall state the amount of the consideration to be paid
for them and the amount paid. Shares may be held and recorded in electronic
form, or through alternative media, if so authorized by the Board of Directors;
whereupon such shares will be deemed to be "certificated" for all purposes under
these Second Amended and Restated By-Laws. All certificates shall be signed in
the name of the Corporation by the Chairman of the Board or Vice Chairman of the
Board or the President or Vice President and by the Treasurer or an Assistant
Treasurer or the Secretary or any Assistant Secretary, certifying the number of
shares and the class or series of shares owned by the stockholder. Any or all of
the signatures on the certificate may be facsimile, electronic, or represented
on other media. In case any officer, transfer agent, or registrar who has signed
or whose facsimile signature has been placed on a certificate shall have ceased
to be that officer, transfer agent, or registrar before that certificate is
issued, it may be issued by the Corporation with the same effect as if that
person were an officer, transfer agent, or registrar at the date of issue.
 
         SECTION 6. Lost Certificates. Except as provided in this Section 6 of
Article VIII, no new certificates for shares shall be issued to replace an old
certificate unless the latter is surrendered to the Corporation and canceled at
the same time. The Board of Directors may, in case any share certificate or
certificate for any other security is lost, stolen, or destroyed,
 
                                      -14-
 
<PAGE>
 
authorize the issuance of a replacement certificate on such terms and conditions
as the board may require, including provision for indemnification of the
Corporation secured by a bond or other adequate security sufficient to protect
the Corporation against any claim that may be made against it, including any
expense or liability, on account of the alleged loss, theft, or destruction of
the certificate or the issuance of the replacement certificate.
 
         SECTION 7. Representation of Shares of other Corporations. The Chairman
of the Board, the President, or any Vice President, or any other person
authorized by resolution of the Board of Directors or by any of the foregoing
designated officers, is authorized to vote on behalf of the Corporation any and
all shares of any other corporation or corporations, foreign or domestic,
standing in the name of the Corporation. The authority granted to these officers
to vote or represent on behalf of the Corporation any and all shares held by the
Corporation in any other corporation or corporations may be exercised by any of
these officers in person or by any person authorized to do so by a proxy duly
executed by these officers.
 
         SECTION 8. Construction and Definitions. Unless the context requires
otherwise, the general provisions, rules of construction, and definitions in the
General Corporation Law of Delaware shall govern the construction of these
Second Amended and Restated Bylaws. Without limiting the generality of this
provision, the singular number includes the plural, the plural number includes
the singular, and the term "person" includes both a corporation and a natural
person.
 
                                   ARTICLE IX
 
                                   AMENDMENTS
 
         SECTION 1. Amendments. These Second Amended and Restated Bylaws may be
altered, amended or repealed, or new bylaws may be adopted, in the manner
provided in the Certificate of Incorporation.
 
         The undersigned, duly qualified and acting Secretary of Ascential
Software Corporation, a Delaware corporation, hereby certifies the foregoing to
be a true and complete copy of the Second Amended and Restated Bylaws of the
said Ascential Software Corporation, as currently in force and effect.
 
                                *     *     *
 
                                      -15-
 
<PAGE>
 
         WITNESS, the hand of the undersigned and the seal of the said Ascential
Software Corporation, this 15th day of April, 2003.
 
                                                  ASCENTIAL SOFTWARE CORPORATION
 
                                                  By: /s/ Scott N. Semel
                                                      --------------------------
                                                  Name: Scott N. Semel
                                                  Title: Secretary